Organic electroluminescence element and method of manufacturing the same

Abstract

The present invention provides an organic electroluminescence element in which an anode layer 2, a light emitting unit 3, and a cathode layer 4 which each have optical permeability are stacked on a transparent substrate 1, the cathode layer 4 including a first charge generation layer 4 a and a cathode 4 c. The cathode 4 c is formed by way of a facing target sputtering method. Even in the case where a cathode material which has optical permeability is used, the organic electroluminescence element is driven at a low applied voltage, has no angle dependability of an emission spectrum, and has high luminous efficiency.

1 . An organic electroluminescence element in which an anode layer, a light emitting unit having at least one light emitting layer, and a cathode layer are stacked on a transparent substrate, wherein
 said anode layer, said light emitting unit, and said cathode layer all have optical permeability, and   said cathode layer has a laminate structure including a first charge generation layer, which contains at least an electron accepting substance, and a cathode.   
   
   
       2 . The organic electroluminescence element as claimed in  claim 1 , wherein said cathode layer is provided with a metal oxide layer between said first charge generation layer and said cathode. 
   
   
       3 . The organic electroluminescence element as claimed in  claim 1  or  2 , wherein said cathode is made of a metal having a work function of 4.0 eV or more. 
   
   
       4 . The organic electroluminescence element as claimed in  claim 2 , wherein said metal oxide layer is made of either a molybdenum oxide, a vanadium oxide, or a tungstic oxide. 
   
   
       5 . The organic electroluminescence element as claimed in claim  1 , wherein a plurality of said light emitting units are connected in series through the second charge generation layer to provide a multi-photon structure. 
   
   
       6 . The organic electroluminescence element as claimed in  claim 1 , wherein light is extracted from either said anode layer side or said cathode layer side, and an optical diffusion reflection layer is provided outside the cathode layer or the anode layer which is located on the opposite side of said light extraction side. 
   
   
       7 . A method of manufacturing an organic electroluminescence element according to a method of manufacturing the organic electroluminescence element as recited in  claim 1 , wherein the cathode of said cathode layer is formed by way of a facing target sputtering method.